<template>
<div>
    <router-link tag="div" to="/" class="header-abs" v-show="showAbs">
        <div class="iconfont header-abs-back">&#xe624;</div>
    </router-link>
    <div class="header-fixed" v-show="!showAbs" :style="opacityStyle">
      <router-link to="/">
        <div class="iconfont header-fixed-back">&#xe624;</div>
      </router-link>
        景点详情
    </div>
</div>
</template>

<script>

export default {
  name: 'DetailHeader',
  data () {
    return {
      showAbs: true,
      opacityStyle: {
        opacity: 0
      }
    }
  },
  methods: {
    handleScroll () {
      const top = document.documentElement.scrollTop
      if (top > 60) {
        let opacity = top / 140
        opacity = opacity > 1 ? 1 : opacity
        this.opacityStyle = {
          opacity
        }
        this.showAbs = false
      } else {
        this.showAbs = true
      }
    }
  },
  activated () {
    window.addEventListener('scroll', this.handleScroll)
  },
  deactivated () {
    window.removeEventListener('scroll', this.handleScroll)
  }
}
</script>

<style lang="stylus" scoped>
@import '~styles/varibles'
 .header-abs
  position: absolute
  left: .2rem
  top: .2rem
  width: .8rem
  height: .8rem
  line-height : .8rem
  border-radius : .4rem
  text-align:center
  background : rgba(0, 0, 0, .8)
  .header-abs-back
   color: #fff
   font-size: .4rem
 .header-fixed
   z-index: 2
   position: fixed
   top: 0
   left: 0
   right: 0
   height: $headerHeight
   line-height: $headerHeight
   text-align: center
   color: #fff
   background: $bgColor
   font-size: .32rem
   .header-fixed-back
    position: absolute
    top: 0
    left: 0
    width: .64rem
    text-align: center
    font-size: .4rem
    color: #fff
</style>
